Gas exchange system flow configuration with thermally insulated sample chamber

Inventors

Johnson, Mark A. • Parr, Andrew S. • Eckles, Robert D.

Assignees

Li Cor Inc

Abstract

System flow path designs that minimize the impact of gas diffusion sources and sinks. By reducing the magnitude of parasitic sources and sinks, lower rates of photosynthesis and transpiration can be more accurately measured, e.g., without the need for extensive empirical compensation. The gas exchange analysis system includes a sample chamber having an inlet and an outlet, wherein the internal surface(s) of the chamber defining the measurement volume are metal plated. The system also typically includes a source of gas coupled with the inlet of the sample chamber, and a gas analyzer coupled with the outlet of the sample chamber and configured to measure a concentration of one or more gases exiting the chamber, whereby the metal plated internal surface(s) of the chamber reduces sorption of the one or more gases within the chamber.

Core Innovation

The invention provides a gas exchange analysis system for analyzing a sample using a sample chamber defining a measurement volume for analysis of a sample. The sample chamber has an inlet and an outlet, and the internal surface(s) of the chamber defining the measurement volume comprise a nickel plated plastic material. A source of gas is coupled with the inlet of the sample chamber, and a gas analyzer is coupled with the outlet of the sample chamber to measure a concentration of one or more gases exiting the chamber.

The system is configured so that the nickel plated internal surface(s) of the chamber reduce sorption of the one or more gases within the chamber. The disclosure also addresses accuracy by minimizing diffusion-driven parasitic gas sources and sinks via a sensor-head-proximal flow splitting configuration and reduced pneumatic path length.

The disclosure further describes thermally insulating sample chamber construction using direct digital manufacturing with plastic or composite materials, together with metal plating compatible with complex internal passages. The described implementation includes example experimental results using reduced CO2 concentration difference (Cs−Cr) with the head-proximal flow splitting and plated chamber surfaces.

Claims Coverage

The independent claim defines a gas exchange analysis system with a sample chamber whose internal measurement-volume surfaces are nickel plated plastic to reduce sorption of measured gases. Dependent claims refine the system by specifying the gas plumbing layout, the nickel plating approach, the plastic materials, the gases measured, the analyzer type, and representative sample types and alternative internal-surface material options.

Across the claim set, the inventive focus is the use of nickel plated plastic internal measurement-volume surfaces in the sample chamber to reduce sorption of measured gases, combined with a coupled gas source and an outlet gas analyzer measuring gas concentration. Dependent claims further specify remote reservoir plumbing, electroless nickel plating, particular plastic substrates, CO2/H2O measurement, an IRGA gas analyzer, and related refinements.

Stated Advantages

Documented Applications